(help) java.lang.runtimeexception unable to start activity componentinfo

Question

I am new to programming and Im sorry if this type of question has been asked tons of times already. and i am so confused with those errors please help ... Here is My MainActivity.java

package id.romi.androidquiz;

import java.util.Collections;
import java.util.List;


import id.romi.androidquiz.entity.Quiz;
import id.romi.androidquiz.util.DBAdapter;
import id.romi.androidquiz.util.Utils;

import com.actionbarsherlock.app.SherlockActivity;



import android.app.AlertDialog;
import android.content.Intent;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends SherlockActivity implements OnClickListener
{
    private static final String TAG = MainActivity.class.getName();

    private TextView    soal, user, txtScore, soalCounter, Timer;
    private Button      btnNext;
    private RadioGroup  rg_answer;
    private RadioButton rb_A, rb_B, rb_C, rb_D;


    private DBAdapter   mDb;
    private List<Quiz>  mListQuiz;
    private Quiz        mQuiz;
    private CountDownTimer  mCountDownTimer;

    private int         mScore;
    private int         mTime = 0;
    private int         currentSoal = 0;
    private static final int    milisecond  = 1000;
    private static final int    second = 90;
    private static final int    detik  = second * milisecond;





    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //savedInstanceState instance dbAdapter
        mDb = DBAdapter.getInstance(this);

        // get data soal
        mListQuiz = mDb.getAllSoal();

        // acak list 
        Collections.shuffle(mListQuiz);
        setupView();

        // tampilkan input username
        showInputUser();

    }


    private void mulaiQuiz()
    {
        setupSoal();
        setupTimer();
    }

    private void showInputUser()
    {
        LayoutInflater mInflater = LayoutInflater.from(this);
        View v = mInflater.inflate(R.layout.input_user, null);

        final AlertDialog dialog = new AlertDialog.Builder(this).create();

        dialog.setView(v);
        dialog.setTitle("Input Username");

        final Button btnOk = (Button) v.findViewById(R.id.btnOk);
        final EditText inputUser = (EditText) v.findViewById(R.id.inputUser);

        btnOk.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                user.setText(inputUser.getText().toString());
                mulaiQuiz();
                dialog.dismiss();

            }
        });
        dialog.show();

        }

        private void setupTimer()
        {
            mCountDownTimer = new CountDownTimer(detik, 1000)
            {
                @Override
                public void onTick(long millisUntilFinished)
                {
                    // TODO Auto-generated method stub
                    Timer.setText("time: " + millisUntilFinished / 1000 + "detik");
                    mTime = (int) (millisUntilFinished / 1000);
                }

                @Override
                public void onFinish()
                {
                    // TODO Auto-generated method stub
                    Timer.setText("time: 0 detik");
                    Toast.makeText(MainActivity.this, "Waktu Habis", Toast.LENGTH_SHORT).show();
                }
            };
            mCountDownTimer.start();

            }

    private void setupSoal()
    {
        Utils.TRACE(TAG, "Soal ke - " + currentSoal);
        Utils.TRACE(TAG, "Size - " + mListQuiz.size());

        //clear checked radiobutton
        rg_answer.clearCheck();

        //get soal berdasar index
        mQuiz = mListQuiz.get(currentSoal);

        //set counter soal
        soalCounter.setText("Soal ke -" + (currentSoal + 1));
        //set soalnya
        soal.setText(mQuiz.getSoal());

        rb_A.setText("A. " + mQuiz.getJawaban_a());
        rb_B.setText("B. " + mQuiz.getJawaban_b());
        rb_C.setText("C. " + mQuiz.getJawaban_c());
        rb_D.setText("D. " + mQuiz.getJawaban_d());

        currentSoal++;
    }

    private void setupView()
    {
        soal = (TextView) findViewById(R.id.txtSoal);
        soalCounter = (TextView) findViewById(R.id.txtSoalCount);
        txtScore = (TextView) findViewById(R.id.txtScore);
        user = (TextView) findViewById(R.id.txtUser);
        Timer = (TextView) findViewById(R.id.timer);

        txtScore.setText("Score : " + mScore);

        rb_A = (RadioButton) findViewById(R.id.rb_A);
        rb_B = (RadioButton) findViewById(R.id.rb_B);
        rb_C = (RadioButton) findViewById(R.id.rb_C);
        rb_D = (RadioButton) findViewById(R.id.rb_D);
        rg_answer = (RadioGroup) findViewById(R.id.rgAnswer);
        btnNext = (Button) findViewById(R.id.btnNext);

        btnNext.setOnClickListener(this);
    }

    @Override
    public void onClick(View v)
    {
        if (v == btnNext)
        {
            if(getAnswer().equals(mQuiz.getJawaban_benar().toUpperCase()))
            {
                mScore += 10;
                txtScore.setText("Score" + mScore);
                // setupSoal();
            }
            if(currentSoal < mListQuiz.size())
            {
                setupSoal();
            }
            else
            {
                mTime = second - mTime;

                Bundle bundle = new Bundle();
                bundle.putString("user", user.getText().toString());
                bundle.putInt("score", mScore);
                bundle.putInt("time", mTime);

                Intent i = new Intent(MainActivity.this, ResultActivity.class);
                i.putExtras(bundle);
                startActivity(i);
                finish();
            }
            Utils.TRACE(TAG,  "Your score" + mScore);
        }
    }


    private String getAnswer()
    {
        int id = rg_answer.getCheckedRadioButtonId();
        if (id == R.id.rb_A )
        {
        return "A";
        } else if (id == R.id.rb_B )
        {
        return "B";
        } else if (id == R.id.rb_C )
        {
        return "C";
        } else if (id == R.id.rb_D )
        {
        return "D";
        }
        return "";
    }

}

My AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="id.romi.androidquiz"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.Sherlock.Light" >
        <activity
            android:name="id.romi.androidquiz.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity 
            android:name="id.romi.androidquiz.ResultActivity"
            android:label="@string/title_activity_result"
            ></activity>
    </application>

</manifest>

And Finally this is my logcat

10-28 00:40:52.024: I/SQLiteAssetHelper(807): successfully opened database db_quiz
10-28 00:40:52.034: D/AndroidRuntime(807): Shutting down VM
10-28 00:40:52.034: W/dalvikvm(807): threadid=1: thread exiting with uncaught exception (group=0x41465700)
10-28 00:40:52.054: E/AndroidRuntime(807): FATAL EXCEPTION: main
10-28 00:40:52.054: E/AndroidRuntime(807): java.lang.RuntimeException: Unable to start activity ComponentInfo{id.romi.androidquiz/id.romi.androidquiz.MainActivity}: java.lang.NullPointerException
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.os.Handler.dispatchMessage(Handler.java:99)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.os.Looper.loop(Looper.java:137)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.ActivityThread.main(ActivityThread.java:5103)
10-28 00:40:52.054: E/AndroidRuntime(807):  at java.lang.reflect.Method.invokeNative(Native Method)
10-28 00:40:52.054: E/AndroidRuntime(807):  at java.lang.reflect.Method.invoke(Method.java:525)
10-28 00:40:52.054: E/AndroidRuntime(807):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
10-28 00:40:52.054: E/AndroidRuntime(807):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-28 00:40:52.054: E/AndroidRuntime(807):  at dalvik.system.NativeStart.main(Native Method)
10-28 00:40:52.054: E/AndroidRuntime(807): Caused by: java.lang.NullPointerException
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.database.sqlite.SQLiteCursor.getColumnIndex(SQLiteCursor.java:178)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:301)
10-28 00:40:52.054: E/AndroidRuntime(807):  at id.romi.androidquiz.util.DBAdapter.getAllSoal(DBAdapter.java:95)
10-28 00:40:52.054: E/AndroidRuntime(807):  at id.romi.androidquiz.MainActivity.onCreate(MainActivity.java:65)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.Activity.performCreate(Activity.java:5133)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
10-28 00:40:52.054: E/AndroidRuntime(807):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
10-28 00:40:52.054: E/AndroidRuntime(807):  ... 11 more

i add my DBAdapter.java

package id.romi.androidquiz.util;

import id.romi.androidquiz.entity.Quiz;

import java.util.ArrayList;
import java.util.List;

import com.readystatesoftware.sqliteasset.SQLiteAssetHelper;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;


public class  DBAdapter extends SQLiteAssetHelper {
private static final String DB_NAME ="db_quiz";
private static final int DB_VER = 1;

public static final String TABLE_SOAL ="tb_soal";

public static final String COL_SOAL_ID ="id";
public static final String COL_SOAL_SOAL ="soal";
public static final String COL_SOAL_JAWABAN_A ="jawaban_a";
public static final String COL_SOAL_JAWABAN_B ="soal";
public static final String COL_SOAL_JAWABAN_C ="soal";
public static final String COL_SOAL_JAWABAN_D ="soal";


    private static DBAdapter dbInstance = null;
    private static SQLiteDatabase db;
    private String COL_SOAL_JAWABAN_BENAR;



    private DBAdapter(Context context)
    {
        super(context, DB_NAME, null, DB_VER);
    }


    public static DBAdapter getInstance(Context context)
    {
        if(dbInstance == null)
        {
            dbInstance = new DBAdapter(context);
            db = dbInstance.getWritableDatabase();
        }
        return dbInstance;
    }





     @Override

    public synchronized void close()
    {
        super.close();
        if (dbInstance != null)
        {
            dbInstance.close();
        }
    }



    public List<Quiz> getAllSoal()
    {
        List<Quiz> listSoal = new ArrayList<Quiz>();

        Cursor cursor = db.query(TABLE_SOAL, new String[]
                {
                COL_SOAL_ID,
                COL_SOAL_SOAL,
                COL_SOAL_JAWABAN_A,
                COL_SOAL_JAWABAN_B,
                COL_SOAL_JAWABAN_C,
                COL_SOAL_JAWABAN_D,
                COL_SOAL_JAWABAN_BENAR
                }, null, null, null, null, null, null);


    if (cursor.moveToFirst())
    {
        do
        {
            Quiz quiz = new Quiz();
            quiz.setId(cursor.getInt(cursor.getColumnIndexOrThrow(COL_SOAL_ID)));
            quiz.setSoal(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_SOAL)));
            quiz.setJawaban_a(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_JAWABAN_A)));
            quiz.setJawaban_b(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_JAWABAN_B)));
            quiz.setJawaban_c(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_JAWABAN_C)));
            quiz.setJawaban_d(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_JAWABAN_D)));
            quiz.setJawaban_benar(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_JAWABAN_BENAR)));

            listSoal.add(quiz);
        } while (cursor.moveToNext());
    }
    return listSoal;
}
}

Hope You all can Help me to solve my app problem It tells that the errors are in DBAdapter.java for code : "quiz.setJawaban_benar(cursor.getString(cursor.getColumnIndexOrThrow(COL_SOAL_JAWABAN_BENAR)));" and MainActivity.Java for code : "mListQuiz = mDb.getAllSoal();" method getAllSoal() in MainActivity is taken from DBAdapter.java

Answer 1

`From this line in your logcat

10-27 05:30:40.517: E/AndroidRuntime(822): Caused by: java.lang.ClassNotFoundException:
 Didn't find class "android.view.Linearlayout" on path: 
DexPathList[[zip file "/data/app/id.romi.androidquiz-1.apk"],nativeLibraryDirectories=[/data/app-lib/id.romi.androidquiz-1, /system/lib]]

I would say that you probably declare a LinearLayout in your layout file as

<Linearlayout>

when it should be

<LinearLayout>

notice both capital "L"s

and your terminating tag is probably the same way. Check those and fix them if they are incorrect. If that isn't the problem then please post your activity_main.xml.

Off-topic

In your onClick() you are comparing the Views but it is generally better to compare the ids of the View so it would look more like this

 @Override
public void onClick(View v)
{
    int id = v.getId();  // get the id of the View clicked then switch on it below

    switch (id)
    {
       case R.id.btnNext:
          //code if btnNext was clicked
          break;
       case R.id.idOfAnotherView:
          // more code
          break;
       default:
          //default code
          break;

This way you are comparing the ids and it also allows you to use a switch statement if you want which, IMHO, looks cleaner than a bunch of if/else statements if you will use this code for other Views.

Logcat

Check out this answer on reading your logcat this will help tremendously in preliminary self-debugging and allow you to understand better what are the most relevant parts of your code to post when you are stuck.

Answer 2

A layout file is malformed.

You have a view called a Linearlayout, instead of a LinearLayout on line #42 of your Layout

Learn to read LogCat, as it is very helpful at telling you exactly what the problem is:

Caused by: android.view.InflateException: Binary XML file line #42: Error inflating class Linearlayout Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.Linearlayout"

Edit

After editing your original post, you now have another error, completely unrelated to the first:

Caused by: java.lang.NullPointerException MainActivity.onCreate(MainActivity.java:65)

According to your LogCat, this is where your error now lies. Please try to scan your LogCat for familiar names and line numbers if it throws errors, as I said, it is a really good tool for debugging, as it shows you exactly what failed where.